Showing papers by "Edward S. Fry published in 1993"

Atomic Coherence Effects Within the Sodium D1 Line - Lasing Without Inversion via Population Trapping

Abstract: Atomic coherence effects within the sodium ${\mathit{D}}_{1}$ line are shown to lead to the suppression of optical pumping, to the switching of light on and off when the coherence effects are turned on and off, and especially to lasing without inversion

Directed positioning of micronuclei in Paramecium tetraurelia with laser tweezers : absence of detectible damage after manipulation

Abstract: Possible covert damage from the use of the laser optical force trap (laser tweezers) to reposition micronuclei in Paramecium tetraurelia was assessed by measuring proliferation rates and postautogamous survival and mutation rates of cells after laser manipulations. No differences in subsequent daily proliferation rates among laser manipulated and various control classes of cells were seen. Similarly, the rates of postautogamous lethality and of "slow growth mutations" after repositioning of both micronuclei were not different from such rates in unmanipulated controls. In spite of extensive manipulations of micronuclei by the laser tweezers, there is no evidence of any damage induced by these manipulations. The laser tweezers therefore appears to be a tool of benign effect upon living cells, with tremendous potential use in many cell and developmental biological investigations.

On lasing without inversion within the sodium D 1 line

Abstract: We present and analyze a simple scheme demonstrating lasing without inversion (LWI) within the Na D1 line, i.e., within the hyperfine manifolds of the 3 2P1/2 and 3 2S1/2 states.